John (1780-????)
William, Jr. (~1785-1842) — m. Catherine Robinson in 1804
Charlotte (1787-1887) — m. James King Harris
William was born in South Carolina to John MacKay (~1730-~1817) from Calgarie, Caithness, Scotland and Sarah McKinnie (1732-~1772) from Edgecombe County, North Carolina. His place of birth is variously said to have been Charleston, or Camden in Kershaw County. His family name has several different spellings.
I know almost nothing about Margaret.
William and Margaret married about 1776. William fought in the Revolutionary War, rising to the rank of major, although in what outfit I don’t know.
After Margaret’s death, William married Elizabeth ??? about 1788. I don’t know whether they had children.
In 1794 he married for a third time, to Nancy White (1775-1857), in Camden, Kershaw County, South Carolina. Their children:
Elizabeth (1797-1898) — m. William H. Deaver
Thomas (1802)
Harriet (1805-1851) — m. ??? Shaver; m. David Dickson Farr
Nancy (1808-1876) — m. William C. Morton
Lewis (1812)
Violet Mahala (1813-1871)
Sarah L. (1815-23 Jan 1861) — m. John Lemon Moore around 1830; m. John Routh
By 1804 at the latest, William had moved west to Blount County, Tennessee, south of Knoxville.
The 1830 census for Sumner County, Tennessee northeast of Nashville listed a William McKay claiming to be in his sixties, with a wife in her forties. The household included three men and a woman all in their twenties, a girl age 15-19, and two boys 10-14. The data don’t make this a great fit for William and family, but all the other William McKees or McKays in 1830 Tennessee were even less plausible candidates.
William died in 1838 in Roane County, Tennessee, west of Knoxville. He’s reportedly buried in Blount County.
The 1840 census for Sumner County, northeast of Nashville, showed a household headed by a Nancy McKey, supposedly in her 40s, with two young boys, two teen girls, and a woman in her twenties. I can’t find Nancy in 1850. She reportedly died in 1857.
No information
William has his own entry in the family tree.
Charlotte married James King Harris. She lived to the reported age of 100. The 1870 census listed her in Calhoun, Georgia. She died there in 1887 and is buried in Mars Hill Cemetery, Calhoun as Charlotte McKey Harris.
Elizabeth married William H. Deaver. She lived in Graham County, North Carolina, reportedly to the age of 101. She is buried in the Old Mother Church Cemetery, Robbinsville, Graham County.
Sarah, the youngest, married John Lemon Moore around 1830. They lived in Blount County, Tennessee.
https://www.geni.com/people/Major-William-MacKay/6000000015626719347 -- Family details
https://www.familysearch.org/ark:/61903/1:1:XHT1-KP9 -- 1840 census, probably William’s widow Nancy
https://www.familysearch.org/ark:/61903/1:1:MCSP-KLC -- 1870 census, Charlotte
https://www.findagrave.com/memorial/65688747 -- 1887 grave of Charlotte
https://www.familysearch.org/ark:/61903/1:1:XHP4-R7Z -- 1830 census, poss. William